Communication systems may utilize sub-carriers to modulate communicated information. Digital communication systems may sample signals prior to processing the information modulated by the sub-carrier. Digital communication systems may perform a vast array of operations on received signals, including comparing and analyzing signals received at different instances in time.
For example, in the video communication field, a video signal processing system may analyze information in adjacent field or frame lines to determine various characteristics of the incoming video information. The video signal processing system may also compare corresponding field or frame lines in adjacent video fields or frames to determine various characteristics of the incoming video information. The video signal processing system may, for example, perform two-dimensional or three-dimensional comb filtering on an incoming video signal to determine chrominance and luminance information contained in the video signal. Such filtering may involve, for example, utilizing a plurality of field lines in a particular video field (i.e., two-dimensional comb filtering), and may additionally involve, for example, utilizing corresponding field lines in temporally separate video fields or frames (i.e., three-dimensional comb filtering).
It is often desirable, when processing signals received at different times, over different channels or over, for example, different media, to align the signals being processed. This alignment may generally be a temporal alignment, but may also be viewed, for example, as a phase alignment. For example, when processing lines from two video fields in an interlaced video stream, it may be desirable to align the phases of the respective sub-carriers of the lines from the two video fields. Such signals may also have been digitally sampled, in which case, it may be desirable to align the corresponding digital data samples to sample and sub-sample accuracy.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.